The sense of touch provides essential feedback to surgeons performing interventions. For example, this type of feedback can help a surgeon in discriminating between different tissues, or to locate within a given tissue a specific portion on which an intervention must be performed or, conversely, on which accidental manipulations should be avoided.
There has been a move in recent years toward minimally invasive surgeries. In this type of surgery, a surgical instrument is inserted through a relatively small opening, or a blood vessel, in the body of a patient. This deprives the surgeon from direct access to the tissues and, therefore, greatly diminishes the quantity and quality of information that is available to the surgeon, such as tactile feedback. Also, there have been many attempts to develop systems for remotely performing surgery using robots. Once again, in these types of systems, tactile feedback is not provided to the surgeons.
There have been attempts to provide devices for restoring, at least in part, this feedback. For example, some surgical tools include force sensors that can sense the force exerted between the two jaws of a grasper. At the other end of the tool, handles operated by the surgeon are attached to actuators that reproduce the forces sensed by the grasper. However, these types of devices can provide only force feedback; in addition they are not able to discriminate spatially over the tissue grasped between the two jaws of the grasper. Also, only relatively crude measurements are provided and, therefore, only a relatively crude feedback is provided to the surgeon.
The need to measure contact force and the softness of the tissue is also seen in catheter based surgery. Indeed, in this type interventions, surgeons often needs to know how much force is applied to a tissue by the tip or body of a catheter. In addition, integration of softness sensing to such applications can help in differentiating tissues. While some techniques are already used in some systems to sense the softness of tissues, for example optic based techniques, such techniques are inefficient in applications in which there is blood flow. For example, in anuloplasty heart surgery, differentiating leaflet tissues from surrounding tissues and finding suitable locations to insert the anchor is a critical to success of the intervention.
Accordingly, there is a need in the industry to provide an improved system for sensing and displaying softness and force. An object of the present invention is therefore to provide such a system.